The word prompt was smooth. Click on image to enlarge.
Note: The words I have used in the work above are not scripture or paraphrase - but inspired by my heart's understanding of the passage.
A voice of one who cries: Prepare in the wilderness the way of the Lord [clear away the obstacles]; make straight and smooth in the desert a highway for our God! Every valley shall be lifted and filled up, and every mountain and hill shall be made low; and the crooked and uneven shall be made straight and level, and the rough places a plain. And the glory (majesty and splendor) of the Lord shall be revealed, and all flesh shall see it together; for the mouth of the Lord has spoken it. Isaiah 40:3-4 Amplified